1. Field of the Invention
The present invention relates to a lancing device provided with an lancing element capable of reciprocating for pricking the skin of a human subject, for example.
2. Description of the Related Art
To conduct medical testing such as measurement of the glucose level, it is necessary to obtain a sample of blood from the human subject. Conventionally, to obtain a blood sample, use is made of a lancing device provided with a lancing element (such as a needle) to prick the skin (see JP-A-2013-517056, for example).
FIG. 22 depicts a known lancing device. The illustrated lancing device X includes a housing 91 in which a lancet holder 92 and a spring 93 are accommodated. The housing 91 may be made of a resin and have a generally cylindrical shape. The lancet holder 92 has the same central axis as the housing 1, and includes a tubular member for holding a lancet (not shown) provided with a needle extending in the x1 direction. The spring 93 is provided for causing the lancet holder 92 to advance in the x1 direction. For causing the lancet holder 92 to retreat in the x2 direction, the lancing device X may preferably include another spring. In use, a lancet is fixed into the lancet holder 92, and then the compressed spring 93 is released to propel the lancet holder 92 forward in the x1 direction. Hence, the needle of the lancet will prick the skin of the subject, and thereafter the lancet holder 92 is caused to retreat in the x2 direction by the additional spring.
In the lancing device X, a projection 92a is formed on the lancet holder 92, and a guide slit 91a is formed on the housing 91. The projection 92a extends to the outside of the housing 91 through the slit 91a. Since the projection 92a is guided along the guide slit 91a, the lancet holder 92 can be properly moved in the advancing direction x1 and the retreating direction x2 without causing positional deviation. The housing 91 includes a cantilevered stopper 91b having a fixed end (x2-side end) and a free end (x2-side end). As seen from the figure, the x1-side end of the guide slit 91a is defined by the stopper 91b. In use, the lancet holder 92 is caused to advance in the x1 direction, and the projection 92a will collide with the stopper 91b, thereby checking the stroke of the lancet holder 92. Since the stopper 91b is cantilevered, the impact of the collision is alleviated. In this manner, it is possible to prevent the lancing element of the lancet (which is held by the lancet holder 92) from pricking the skin with excessive momentum, which contributes to the alleviation of pain the user of the lancing device may feel.
With the known lancing device, however, the lancing holder 92 tends to keep quivering (due to the spring 93 and the additional spring) within the housing after the skin is pricked. Such quivering can make the user uncomfortable with the use of the lancing device.